Electronic apparatus

ABSTRACT

An electronic apparatus for use in recording and/or playing back audio or video signals includes a six-sided housing of which at least a pair of opposite sides are arranged not parallel to each other, and a signal processor unit mounted in the housing and including at least a circuit board which has a degree of rigidity. The circuit board is arranged with its main side facing the non-parallelly arranged, paired opposite sides of the housing. This prevents the generation of resonance between the housing and the circuit board caused by a stress of vibration introduced to the housing and the circuit board, thus hardly allowing the audio or video signals to deteriorate their recording and/or playback properties.

TECHNICAL FIELD

The present invention relates to an electronic apparatus for use inrecording and/or playing back audio or video signals and moreparticularly, to an electronic apparatus in which excessive vibrationcaused by resonance on its circuit board which constitutes a signalprocessor and is mounted in a housing of the apparatus can be prevented.

BACKGROUND ART

A disk playback apparatus using a disk recording medium has been knownas such an electronic apparatus for recording and/or playing back anaudio signal and a video signal.

As shown in FIGS. 1 and 2, such a known disk playback apparatus 100 hasa housing 101 serving as a main body thereof The housing 101 has arectangular block shape comprising a top panel 102 forming the top sidethereof, a bottom panel 103 forming the bottom side thereof, a frontpanel 104 forming the front side thereof, a back panel 105 forming theback side thereof, and two, left and right, side panels 106 and 107forming the left and right sides thereof More particularly, the housing101 is shaped by assembling with any two opposite sides arrangedparallel to each other; the top panel 102 and the bottom panel 103, thefront panel 104 and the back panel 105, and the left panel 106 and theright panel 107.

A support leg 108 made of a vibration absorbing material such as rubberis mounted to each corner of the bottom panel 103 of the housing 101.The housing 101 is placed with its support legs 108 directly on aplatform 109 such as a table or a bed.

A first circuit board 111 and a second circuit board 112 serving as aplayback unit and a signal processor of the disk playback apparatus 100are installed in the housing 101. The circuit boards 111 and 112 areshaped of a flat sheet-like form which is made of a synthetic resinmaterial having a degree of rigidity and located in the housing 101 soas to extend in parallel to both the top panel 102 and the bottom panel103.

Also, a disk rotating mechanism 113 for rotating the recording medium oran optical disk 99 of the disk playback apparatus 100 is mounted in thehousing 101. The disk rotating mechanism 113 has a spindle motor 114 anda disk table 116 mounted to the distal end of a spindle 115 of thespindle motor 114, as shown in FIG. 1. The disk rotating mechanism 113is secured with its spindle motor 114 fixedly joined to a base 117 inthe housing 101. In particular, the spindle motor 114 is anchored to thebase 117 so that its spindle 115 extends vertical to the top panel 102and the bottom panel 103 which are arranged parallel to each other. Thedisk table 116 on which the optical disk 99 is loaded is mounted to thedistal end of the spindle 115 so that its optical disk 99 loadingsurface is vertical to the spindle 115 and it can rotate together withthe optical disk 99.

Since the loading surface of the disk table 116 extends vertical to thespindle 115, the optical disk 99 when loaded on the disk table 116 issupported at its main side parallel to the top panel 102 and the bottompanel 103.

As not shown, a loudspeaker unit for playing back the audio signal readout from the optical disk 99 to emit acoustic sound is also installed inthe housing 101.

The disk playback apparatus 100 having the foregoing arrangement isplaced with its support legs 108, mounted to the bottom panel 103 of thehousing 101, directly on the platform 109 and during the playbackaction, its housing 101 receives external acoustic power or vibrationfrom the platform 109 or the ambient space. The vibration received fromthe platform 109 may be attenuated by the support legs 108 made of thevibration absorbing material and prevented from direct propagation tothe housing 101 itself and the inside of the housing 101. However, theexternal acoustic power or vibration from the ambient space is directlytransmitted to the housing 101 of the apparatus and produces asignificant of vibration on the housing 101.

Also, the disk rotating mechanism 113 in the disk playback apparatus 100generates vibration when it starts driving. The vibration from the diskrotating mechanism 113 is transmitted via the base 117 to and vibratesthe first circuit board 111 and the second circuit board 112. Moreover,the sound emitted from the loudspeaker unit propagates to and vibratesthe first circuit board 111 and the second circuit board 112.

In the conventional disk playback apparatus 100 as an electronicapparatus, the top panel 102 and the bottom panel 103 of the housing 101facing each other extend parallel to each other while the first 111 andthe second circuit board 112 in the housing 101 are arranged parallel toboth the top panel 102 and the bottom panel 103. This causes thevibration generated on the top panel 102, the bottom panel 103, and thetwo circuit boards 111 and 112 to repeat reflection between the toppanel 102 and the first circuit board 111, between the bottom panel 103and the second circuit board 112, and between the first circuit board111 and the second circuit board 112, as denoted by the arrow in FIG. 1,thus creating unwanted resonance between the top panel 102 and each ofthe two circuit boards 111 and 112 and between the bottom panel 103 andeach of the two circuit boards 111 and 112. The resonance will thentrigger excessive vibration on the top panel 102, the bottom panel 103,and the first circuit board 111 and the second circuit board 112 ofwhich the amplitude is greater than that of the original vibrationgenerated in the housing 101 or of the external vibration introduced tothe housing 101.

The support legs 108 of the disk playback apparatus 100 are identical inheight. While the disk playback apparatus 100 is placed with its supportlegs 108 directly on the platform 109, its bottom panel 103 becomesparallel to the platform 109. This causes the vibration derived from thebottom panel 103 or the platform 109 to repeat reflection between thebottom panel 103 and the platform 109, as denoted by the arrow in FIG.1, hence creating a significant resonance between the bottom panel 103and the platform 109. Accordingly, the resonance will trigger excessivevibration on the bottom panel 103 of which the amplitude is greater thanthat of the external vibration introduced to the bottom panel 103. Theexcessive vibration on the bottom panel 103 repeats reflection betweenthe first circuit board 111 and the second circuit board 112 andproduces greater resonance which then vibrates the two circuit boards111 and 112 to a higher amplitude.

The excessive vibration on the two circuit boards 111 and 112 and thuselectronic components of the circuit boards 111 and 112 impairs theaction of the signal processor unit on the circuit boards 111 and 112.Particularly in the disk playback apparatus as an electronic apparatus,the audio or video signal read out from an optical disk may be addedwith unwanted noise components caused by the vibration and itsproperties will be declined in the playback.

DISCLOSURE OF THE INVENTION

It is an object of the present invention to provide an electronicapparatus capable of recording and/or playing back audio signals andvideo signals while preventing the declination of the recording and/orplayback properties of the signals.

It is another object of the present invention to provide a novelelectronic apparatus which receives no effect of the vibrationintroduced from outside.

It is a further object of the present invention to provide an electronicapparatus which is improved in selecting the materials of a housing andcircuit boards without limitations in order to avoid the effect ofvibration introduced from outside and can thus be decreased in the costof production.

For achievement of the object of the present invention, an electronicapparatus is provided for use in recording and/or playing back audio orvideo signals, comprising: a six-sided housing of which at least a pairof opposite sides are arranged not parallel to each other; and a signalprocessor unit mounted in the housing. The signal processor unitincludes at least a circuit board which has a degree of rigidity and isinstalled in the housing.

Another electronic apparatus according to the present invention isprovided for use in recording and/or playing back audio or videosignals, comprising: a six-sided housing of which at least a pair ofopposite sides are arranged not parallel to each other; and a signalprocessor unit mounted in the housing and including at least a circuitboard which has a degree of rigidity. The circuit board is arranged withits main side facing the paired opposite sides of the housing, wherebythe generation of resonance between the main side of the circuit boardand the paired opposite sides of the housing will be prevented.

A further electronic apparatus according to the present invention isprovided for use in recording and/or playing back audio or videosignals, comprising: a six-sided housing of which at least a pair ofopposite sides are arranged not parallel to each other; and a playbackunit mounted in the housing for playing back a disk recording medium.The playback unit includes at least a circuit board of a flat sheet-likeshape which has a degree of rigidity and is arranged with its main sidefacing the paired opposite sides of the housing, whereby the generationof resonance between the main side of the circuit board and the pairedopposite sides of the housing will be prevented.

A still further electronic apparatus according to the present inventionis provided for use in recording and/or playing back audio or videosignals, comprising: a six-sided housing; and a signal processor unitmounted in the housing and including at least a circuit board which hasa degree of rigidity. The circuit board is arranged not parallel to atleast a pair of opposite sides of the housing, whereby the generation ofresonance between the circuit board and the paired opposite sides of thehousing facing the circuit board will be prevented.

A still further electronic apparatus according to the present inventionis provided for use in recording and/or playing back audio or videosignals, comprising: a six-sided housing; and a playback unit mounted inthe housing for playing back a disk recording medium. The playback unitincludes at least a circuit board which has a degree of rigidity and isarranged with its main side facing a pair of opposite sides of thehousing, whereby the generation of resonance between the circuit boardand the paired opposite sides of the housing facing the circuit boardwill be prevented.

The playback unit may have a disk rotating mechanism for rotating thedisk recording medium. The disk rotating mechanism may be arranged sothat the disk recording medium loaded thereon is not parallel to each ofthe paired opposite sides of the housing.

Other objects of the present invention and practical advantages obtainedby the present invention will be more apparent from the followingdescription of embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional side view showing a schematic constructionof a conventional disk playback apparatus;

FIG. 2 is a cross sectional view taken along the line II—II of FIG. 1;

FIG. 3 is a perspective view of a disk playback apparatus according tothe present invention;

FIG. 4 is a cross sectional view taken along the line IV—IV of FIG. 3;

FIG. 5 is a cross sectional view taken along the line V—V of FIG. 3;

FIG. 6 is a characteristic diagram showing the measurements of acousticpressure when tone burst has been emitted in a housing of each of theconventional disk playback apparatus and the disk playback apparatus ofthe present invention;

FIG. 7 is a characteristic diagram showing the measurement of a changein the amplitude when tone burst has been emitted in the housing of eachof the conventional disk playback apparatus and the disk playbackapparatus of the present invention;

FIG. 8 is a schematic view showing a circuit board arranged at an anglein the housing where the acoustic pressure and a change in the amplitudeare measured;

FIG. 9 is a characteristic diagram showing the measurements of acousticpressure when external vibration has been introduced to the housing ofeach of the conventional disk playback apparatus and the disk playbackapparatus of the present invention; and

FIG. 10 is a characteristic diagram showing the measurements of a changein the amplitude when external vibration has been introduced to thehousing of each of the conventional disk playback apparatus and the diskplayback apparatus of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in the form of a disk playbackapparatus provided with an optical disk as the recording medium.

The disk playback apparatus 1 according to the present invention has ahousing 2 acting as the main body as shown in FIGS. 3, 4, and 5. Thehousing 2 is a six-sided body comprising a top panel 3 forming a topside of the housing 2, a bottom panel 4 forming a bottom side of thehousing 2, a front panel 5 forming a front side of the housing 2, a backpanel 6 forming a back side of the housing 2, and two, left and right,side panels 7 and 8 forming both sides of the housing 2.

The top panel 3, the bottom panel 4, the front panel 5, the back panel6, and the two side panels 7 and 8 of the six-sided housing 2 are madeof flat wooden plates, where any two opposite plates panels are arrangednot parallel to each other.

More specifically, each pair of the top panel 3 and the bottom panel 4,the front panel 5 and the back panel 6, and the left panel 7 and theright panel 8 are arranged not parallel to each other. The top panel 3is tilted with its rear end spaced further from the bottom panel 4 asshown in FIGS. 3 and 5 and slopes up towards the back side of thehousing 2. Also, the bottom panel 4 is tilted with its rear end spacedfurther from the top panel 3 as shown in FIG. 3 and 5 and slopes downtowards the back side of the housing 2. The top panel 3 and the bottompanel 4 deviate from each other as they extend from the front side tothe back side of the housing 2 and are thus not parallel to each other.Referring to FIG. 5, the front panel 5 and the back panel 6 deviate fromeach other as they extend from the bottom panel 4 to the top panel 3 andare hence not parallel to each other. Similarly referring to FIG. 4, thetwo, side panels 7 and 8 deviate from each other as they extend from thebottom panel 4 to the top panel 3 and are hence not parallel to eachother.

The bottom panel 4 of the housing 2 has a support leg 9 provided at eachcorner thereof made of a vibration absorbable material such as rubber.The housing 2 is supported by the support legs 9 on a platform 10 suchas a table or a mounting bed. The two support legs 9 on the front panelside are different in height from the other two support legs 9 locatedon the back panel side of the housing 2, as best shown in FIG. 5.Because the height of the front and back support legs 9 is different,the disk playback apparatus 1 of the present invention placed with itssupport legs 9 directly on the platform 10 is maintained with its bottompanel 4 not parallel to the mounting surface 10 a of the platform 10.

Provided on the upper surface of the top panel 3 of the housing 2 are aset of operating buttons 11 for selecting the operation mode and otherfunctions for controlling the disk playback apparatus 1 and a hatch door12 for loading and unloading an optical disk on the disk playbackapparatus 1.

The housing 2 having the foregoing structure contains, first and secondcircuit boards 13 and 14 acting as a playback unit and a signalprocessor unit respectively of the disk playback apparatus 1. The twocircuit boards 13 and 14 are flat substrates made of a synthetic resinimpregnated material which is prepared by impregnating a sheet of paperwith phenol resin or a size of glass fiber with epoxy resin and has adegree of rigidity. As shown in FIG. 5, the first circuit board 13 andthe second circuit board 14 are mounted in the housing 2 with their mainsurfaces kept not parallel to the top panel 3 and the bottom panel 4respectively. More particularly, the first circuit board 13 and thesecond circuit board 14 are situated in the housing 2 with their anglesto the corresponding horizontal surfaces of the top panel 3 and thebottom panel 4 different from each other. In practice, the two circuitboards 13 and 14 are maintained tilting up towards the back side of thehousing 2.

In addition, the first and second circuit boards 13 and 14 installed inthe housing 2 are unparallel not only to the top panel 3 and the bottompanel 4 but also to each other, as shown in FIG. 5. More specifically,the angle between the first circuit board 13 and the horizontal plane isgreater than the angle between the second circuit board 14 located in alower side of the housing 2 and the horizontal plane. Simultaneously,the angle between the first circuit board 13 and the horizontal plane issmaller than the angle between the top panel 3 and the horizontal planeas installed in the housing 2.

It is essential that the first and second circuit boards 13 and 14installed in tilting relationship in the housing 2 are prevented fromtheir main surfaces being at an angle of 45 degrees to the top panel 3and the bottom panel 4.

A disk rotating mechanism 21 for rotating the optical disk 51 which is arecording medium in the disk playback apparatus is installed in thehousing 2. As shown in FIG. 5, the disk rotating mechanism 21 comprisesa spindle motor 22 and a disk table 24 mounted to the distal end of aspindle 23 of the motor 22. The disk rotating mechanism 21 is anchoredwith its spindle motor 22 to a base 25 installed in the housing 2. Thespindle motor 22 is secured to the base 25 so that its spindle 23extends vertical to the mounting surface 10 a of the platform 10 onwhich the disk playback apparatus 1 is placed. The disk table 24 mountedto the distal end of the spindle 23 of the spindle motor 22 has aloading surface 24 a, on which the optical disk 51 is loaded, providedvertical to the spindle 23 for rotation together with the spindle 23.

Because the disk table 24 is arranged with its disk loading surface 24 asitting vertical to the spindle motor 23, the optical disk 51 whenloaded on the disk table 24 becomes at its main side parallel to themounting surface 10 a of the platform 10 on which the disk playbackapparatus 1 is placed but not parallel to the top panel 3 and the bottompanel 4.

An upright wall 26 is provided about the base 25 by which the spindlemotor 22 so that it surrounds the optical disk 51 loaded on the disktable 24. The upright wall 26 is designed to guide the optical disk 51when being loaded onto the disk table 24 for ensuring the precisepositioning on the disk table 24 and also to protect the optical disk 51from physical interruption of other components in the housing 2.

The loading and unloading of the optical disk 51 on the disk table 24are made through a loading opening which is opened and closed with thehatch door 12 mounted on the top panel 3.

Also, a loudspeaker unit for playing back an audio signal from theoptical disk 51 for acoustic reproduction is installed in the housing 2as not shown.

The disk playback apparatus 1 of the present invention having theforegoing arrangement like a conventional disk playback apparatus isplaced with its support legs 9, mounted to the bottom panel 4 of thehousing 2, directly on the platform 10, whereby external acoustic andmechanical vibrations from the platform 10 and the ambient space can betransmitted via the support legs 9 to the housing 2. While themechanical vibration directly transmitted from the platform 10 issuccessfully attenuated by the support legs 9 made of the vibrationabsorbable material, the acoustic vibration from the ambient space isreceived directly by the housing 2 of the disk playback apparatus whichwill thus oscillate. Particularly, the acoustic vibration from theambient space affects the housing 2 whenever the disk playback apparatus1 is placed directly on the platform 10 or hanged in the air.

It is also common in the disk playback apparatus that the action of thedisk rotating mechanism 21 produces vibration which may be transmittedvia the base 25 or the other components to and hence oscillate the firstcircuit board 13 and the second circuit board 14. In addition, soundemitted from the loudspeaker unit is propagated to and oscillate thefirst circuit board 13 and the second circuit board 14.

The vibration on the housing 2 and the circuit boards 13 and 14 isradiated vertically from the surfaces of the panels 3 through 8 of thehousing 2 and the circuit boards 13 and 14 and reflected by the oppositesurfaces of the panels 3 through 8 and the circuit board 13 and 14 inthe housing 2. The vibration received at the opposite surfaces of thepanels 3 through 8 and the circuit board 13 and 14 is reflected with itsreflection angle equivalent to the incident angle.

As described above, each opposite pair of the top panel 3 and the bottompanel 4, the front panel 5 and the back panel 6, the left side panel 7and the right side panel 8 of the six-sided housing 2 are not parallelto each other in the disk playback apparatus 1 of the present inventionThis allows the vibration caused by the external acoustic and mechanicalvibration on the housing 2 and radiated vertically from the surfaces ofthe panels 3 through 8 and the circuit boards 13 and 14 to be reflectedon their opposite surfaces at corresponding angles defined by thenon-parallel arrangement of the opposite panel 3 through 8 and thecircuit boards 13 and 14 in the housing 2 and thus prevented fromreturning back to their starting surfaces. More specifically, thevibration reflected by the panels 3 through 8 and the circuit boards 13and 14 is propagated as denoted by the arrow marks in FIGS. 4 and 5 andnot returned back to its starting surfaces. Accordingly, the vibrationradiated from the panels 3 through 8 and the circuit boards 13 and 14 ishardly interfered by its reflection coming from their opposite surfacesof the panels 3 through 8 and the circuit boards 13 and 14, thusavoiding the generation of unwanted resonation between the oppositesurfaces of the panels 3 through 8, between the top panel 3 and the twocircuit boards 13 and 14, or between the bottom panel 4 and the twocircuit boards 13 and 14. Since no resonation between the oppositesurfaces of the panels 3 through 8 and the circuit boards 13 and 14 inthe housing 2 is allowed, any excessive vibration greater than theinitial vibration on the panels 3 through 8 and the circuit boards 13and 14 will be prevented.

Also, because the bottom panel 4 of the housing 2 in the disk playbackapparatus 1 of the present invention is arranged not parallel to themounting surface 10 a of the platform 10, the vibration propagated fromthe platform 10 or from the bottom panel 4 hardly returns back to itsstarting surface as illustrated with the arrow mark in FIG. 5, henceavoiding resonation between the bottom panel 4 and the platform 10 andpermitting no excessive vibration on the bottom panel 4.

Moreover, because the main side of the optical disk 51 which is loadedon the disk table 24 of the disk rotating mechanism 21 of which thespindle motor 22 is anchored to the base 25 with its spindle 23extending vertical to the mounting surface 10 a of the platform 10 onwhich the disk playback apparatus 1 is placed is set not parallel to thetop panel 3 of the housing 2, resonation will hardly be allowed betweenthe optical disk 51 and the top panel 3. In some cases, the optical disk51 when loaded on and driven by the disk rotating mechanism 21 generatesvibration from its surface deviation. It is however avoided by the abovearrangement that the repeating of such vibration results in resonationbetween the top panel 3 and the optical disk 51.

In the disk playback apparatus 1 of the present invention, each pair ofthe top panel 3 and the bottom panel 4, the front panel 5 and the backpanel 6, and the left side panel 7 and the right side panel 8 of thehousing 2 are arranged not parallel to each other while the firstcircuit board 13 and the second circuit board 14 located opposite to thetop panel 3 and the bottom panel 4 respectively are arranged notparallel to the top panel 3 and the bottom panel 4 respectively and toeach other in the housing 2. This prevents the vibration exerted to orgenerated on the housing 2 from causing resonation between any oppositepair of the panels 3 through 8, between the top panel 4 and each of thetwo circuit boards 13 and 14, and between the bottom panel 5 and each ofthe two circuit boards 13 and 14, hence permitting no excessivevibration on the first circuit board 13 and the second circuit board 14which serve as the playback unit and the signal processor unitrespectively of the disk playback apparatus 1. As the first circuitboard 13 and the second circuit board 14 are prevented from excessivevibration, electronic components mounted on the two circuit boards 13and 14 will hardly suffer from vibration.

Since vibration on the electronic components mounted on the firstcircuit board 13 and the second circuit board 14 as well as the twocircuit boards 13 and 14 themselves is hardly permitted, the action ofthe two circuit boards 13 and 14 or more particularly of the signalprocessor composed of the electronic components on the circuit boards 13and 14 can be performed consistently, hence avoiding the addition ofnoises derived from the vibration to the signals of interest includingan audio playback signal read out from the optical disk 51 and variouscontrol signals. Accordingly, the playback of the signals of interestwill be carried out with optimum effects.

Also, the disk playback apparatus 1 of the present invention allows theoptical disk 51 loaded on and driven by the disk rotating mechanism 21in opposition to the top panel 3 to be set not parallel to the top panel3, thus preventing resonation between the optical disk 51 and the toppanel 3. As the optical disk 51 is prevented from no excessivevibration, it can perform stable movements and will hardly interrupt theaction of the first circuit board 13 and the second circuit board 14with its vibration hence guaranteeing the stable action of the signalprocessor.

With the loudspeaker unit in the housing emitting a tone burst atpredetermined frequency and acoustic pressure, a change in the acousticpressure inside and outside the housing was measured to compare thehousing 101 of a conventional disk playback apparatus 100 such asdescribed previously and the housing 2 of the disk playback apparatus 1of the present invention.

A microphone was located 20 cm above substantially the center of each ofthe top panels 102 and 3 of the housings 101 and 2 respectively and usedfor collecting sounds to measure a change in the acoustic pressureoutside the housings 101 and 2.

Similarly, to measure a change in the acoustic pressure inside thehousings 101 and 2, a microphone was positioned between the firstcircuit board 111 in housing 100 and the top panel 102 and above thefirst circuit board 111 and a microphone was positioned between thefirst circuit board 13 in housing 2 and the top panel 3 and above thefirst circuit board 13. The position of the microphone corresponds tosubstantially the center of the main side of each of the first circuitboards 111 and 13.

When the tone burst having a frequency of 1 kHz and a predeterminedacoustic pressure was emitted for a period denoted by t1 in FIG. 6 orpractically 100 mmsec from the loudspeaker unit in each of the housings101 and 2, the acoustic pressure outside the housings 101 and 2 variedas is expressed by the profile A in FIG. 6.

The acoustic pressure inside the housing 110 of the conventional diskplayback apparatus 100 was varied as denoted by the profile B in FIG. 6.

Also, the acoustic pressure inside the housing 2 of the disk playbackapparatus 1 of the present invention was varied as shown by the profileC in FIG. 6.

As apparent from FIG. 6, the acoustic pressure released from theloudspeaker unit of the conventional disk playback apparatus 100 lasts aperiod of t2 until it decays from its start level and the decaying timeof the acoustic pressure in the disk playback apparatus 1 of the presentinvention is much shorter than t2.

Again to compare between the two housings 101 and 2, was measured achange in the amplitude after emission of the tone burst atpredetermined frequency and acoustic pressure for a predetermined periodof time from the loudspeaker unit in each of the housings 101 and 2 ofthe conventional disk playback apparatus 100 and the disk playbackapparatus 1 of the present invention respectively. The measurement of achange in the amplitude in the housings 101 and 2 was carried out usingan acceleration pickup device, like the microphone of the precedingmeasurement, located between the first circuit board 111 and the toppanel 102 in housing 101, substantially above the first circuit board111, and substantially at the center of the main side of the firstcircuit board 111 and between the first circuit board 13 and the toppanel 2 in housing 2, substantially above the first circuit board 13,and substantially at the center of the main side of the first circuitboard 13.

In this measurement, the tone burst having a frequency of 1 kHz and apredetermined acoustic pressure was emitted for a period of t1 denotedin FIG. 7 or practically 100 mmsec was from the loudspeaker unit in theeach of the housings 101 and 2 and a resultant change in the amplitudewas measured using the acceleration pickup device at the correspondinglocations.

As denoted by the profile D in FIG. 7, the amplitude in the conventionaldisk playback apparatus 100 was kept high during the emission and aftertermination of the emission of the tone burst from the loudspeaker unitand showed no significant sign of decay for a considerable length oftime.

In the disk playback apparatus 1 of the present invention, the amplitudegave no explicit change between the emission and before and after theemission of the tone burst from the loudspeaker unit as is denoted bythe profile E in FIG. 7.

As is apparent from FIGS. 6 and 7, the disk playback apparatus 1 yieldsa smaller change in acoustic pressure resulting from a tone burstemitted from the loudspeaker unit than the conventional disk playbackapparatus 100. This occurs because, in the present invention, eachopposite pair of the panels 3-4, 5-6 and 7-8, are not parallel, just asthe top and bottom panels 3 and 4 are not parallel to each of thecircuit boards 13 and 14. The non-parallel structure of the presentinvention is superior to the conventional disk playback apparatus 100where each opposite pair of the panels 102-103, 104-105, 106-107 are inparallel, just as the top and bottom panels 102 and 103 are parallel toeach of the circuit boards 111 and 112. Therefore, within the diskplayback apparatus 1 the period of decay of the amplitude is minimizedand no excessive vibration of the top panel 3 and the first circuitboard 13 is permitted. This prevents the generation of resonance betweenthe top panel 3 and the first circuit board 13 and protects the toppanel 3 and the first circuit board 13 from suffering from excessivevibration higher than the magnitude of the tone burst output of theloudspeaker unit.

For proving more of the above mentioned advantages of setting oppositepanels of the housing 2 not parallel to each other in the attenuation ofresonance between the two opposite panels, some models were prepared andtested.

A housing 200 of such a cubic shape as shown in FIG. 8 was prepared.Each pair of a top panel 201 and a bottom panel 202, a front panel and aback panel, and a left side panel 203 and a right side panel 204 of thehousing 200 which extended opposite to each other were arranged parallelto each other. A circuit board 205 made of the same rigid material as ofthe first circuit board 13 and the second circuit board 14 was installedin the housing 200 with its main side facing the top panel 201 and thebottom panel 202. The tone burst having a frequency of 1 kHz and apredetermined acoustic pressure similar to one described above wasemitted for an instant of 100 mmsec from a loudspeaker unit mounted inthe housing 200 and its change of acoustic pressure was measured with amicrophone 210 located between the top panel 201 and the circuit board205 and at substantially the center of the circuit board 205. Also, achange in the amplitude was measured at the corresponding location usingan acceleration pickup device.

While the tilting angle θ of the circuit board 205 to the top panel 201was varied in a range from one degree to three degrees, the acousticpressure and a change in the amplitude were measured. It was found thatthe acoustic pressure and a change in its amplitude were substantiallyequal to those measured in the disk playback apparatus of the presentinvention when the tilting angle θ was three degrees. Also, themeasurements were as good as those of the disk playback apparatus of thepresent invention when the tilting angle θ of the circuit board 205 tothe top panel 201 was greater than three degrees.

It is clear from the above result that the angle between any twoopposite panels is preferably greater than three degrees to avoid thegeneration of resonance between the two opposite panels and minimizeexcessive vibration on the panels.

With each of the conventional disk playback apparatus 100 and the diskplayback apparatus 1 of the present invention placed on itscorresponding platform 109 or 10, the acoustic pressure of vibrationproduced when a block of wood having a size of 30 cm×20 cm×10 cm hadbeen dropped on the platform 109 or 10 was measured at differentlocations.

The profile denoted by F in FIG. 9 illustrates the measurement of theacoustic pressure with the microphone located 20 cm above substantiallythe center of each of the top panel 102 and 3 of their respective diskplayback apparatuses 100 and 1 placed on the platforms 109 and 10respectively.

Also, denoted by G and H in FIG. 9 are the measurements of the acousticpressure in the conventional disk playback apparatus 100 and the diskplayback apparatus 1 of the present invention respectively which werepicked up by the microphone located between the first circuit board 111and the top panel 102 and substantially above the first circuit board111 in housing 101, and the microphone located between the first circuitboard 13 and the top panel 3 and substantially above the first circuitboard 13 in housing 2.

Then, a change in the amplitude of vibration generated when a block ofwood having a size of 30 cm×20 cm×10 cm had been dropped on the platform109 or 10 was measured at different locations in the housing 101 or 2with each of the conventional disk playback apparatus 100 and the diskplayback apparatus 1 of the present invention placed on itscorresponding platform 109 or 10.

More specifically, a change in the amplitude in housing 101 was measuredusing an acceleration pickup device located between the first circuitboard 111 and the top panel 102 and substantially above the firstcircuit board 111 while the acoustic pressure was measured using amicrophone. A change in the amplitude in housing 2 was similarlymeasured using an acceleration pickup device located between the firstcircuit board 13 and the top panel 3 and substantially above the firstcircuit board 13 while the acoustic pressure was measured using amicrophone. The resultant measurements are plotted as shown of the diskplayback apparatus 100 in a profile denoted by I in FIG. 10 and of thedisk playback apparatus 1 of the present invention in a profile denotedby J in FIG. 10.

It is apparent from FIGS. 9 and 10 that the acoustic pressure and theamplitude caused by external vibration are kept lower and smaller in thehousing 2 of the disk playback apparatus 1 of the present invention, theamplitude being decayed quickly, than in that of the conventional diskplayback apparatus 100.

As set forth above, there are arranged not parallel to each otherbetween each opposite pair of the panels 3 through 8, between the toppanel 3 and each of the circuit boards 13 and 14, and between the bottompanel 4 and each of the circuit boards 13

Industrial Applicability

The present invention is embodied in the form of an electronic apparatusfor recording and/or playing back audio or video signals which has asix-sided housing, of which at least a pair of opposite sides arearranged not parallel to each other, and a signal processor unitcomposed of at least a circuit board having a degree of rigidity andinstalled in the housing, the circuit board of the signal processorsituated with its main side facing the two non-parallelly arrangedopposite sides of the housing. This prevents the generation of resonancebetween the main side of the circuit board and the two non-parallellyarranged opposite sides of the housing, thus permitting no excessivevibration on the circuit board and ensuring that the audio or videosignals are record and/or played back at their optimum conditions. and14 in the housing 2. Accordingly, when the housing 2 receives a stressof external vibration, it can prevent the generation of resonancebetween any two opposite panels thereof thus allowing no excessivevibration on the first 13 and the second circuit board 14 whichconstitute the signal processor unit. It will hence be ensured that thedata signals including the audio signal and the control signals read outfrom the optical disk 51 are played back at their optimum characteristiccondition without having any unwanted noise components driven from thevibration or with no deterioration of their properties.

In the disk playback apparatus 1 of the present invention, suchexcessive vibration as caused by the internal vibration generated in thehousing 2 or the resonance in the housing 2 derived from externalvibration is restrained regardless of the materials of the housing 2 andthe two circuit boards 13 and 14. This gives more freedom in selectingthe materials of the housing 2 or the first 13 and the second circuitboard 14, contributing to the ease of the production and the low cost ofthe disk playback apparatus 1.

Although the present invention is described in the form of a diskplayback apparatus, it is applicable with equal success to electronicapparatuses for recording and/or playing back audio or video signalsincluding a video tape recorder, a video disk drive, and a televisionreceiver as well as various audio apparatuses including a disk player,where the benefit is identical to that of the disk playback apparatus ofthe embodiment.

What is claimed is:
 1. An electronic apparatus for use in recordingand/or playing back at least one of audio and video signals, comprising:a housing having only six sides of which two opposite sides are a toppanel and a bottom panel arranged not parallel to each other; aplurality of support legs of differing heights arranged on the bottompanel such that the bottom panel is not parallel to a horizontal surfaceon which the electronic apparatus is placed; and a plurality of rigidcircuit boards installed in the housing, wherein at least one of theplurality of circuit boards includes a signal processor unit mountedthereon.
 2. The electronic apparatus according to claim 1, wherein allremaining opposite sides of the housing are respectively arranged notparallel to each other.
 3. The electronic apparatus according to claim1, wherein the plurality of circuit boards are arranged not parallel toeach other and arranged not parallel to any side of the housing.
 4. Anelectronic apparatus for use in recording and/or playing back at leastone of audio and video signals, comprising: a housing having only sixsides of which two opposite sides are a top panel and a bottom panelarranged not parallel to each other; a plurality of support legs ofdiffering heights arranged on the bottom panel such that the bottompanel is not parallel to a horizontal surface on which the electronicapparatus is placed; and a plurality of rigid circuit boards installedin the housing, wherein at least one of the plurality of circuit boardsincludes a signal processor unit mounted thereon, wherein a main side ofeach of the plurality of circuit boards faces the top panel and thebottom panel of the housing.
 5. The electronic apparatus according toclaim 4, wherein all remaining opposite sides of the housing arerespectively arranged not parallel to each other.
 6. The electronicapparatus according to claim 4, wherein the plurality of circuit boardsare arranged not parallel to each other and arranged not parallel to anyside of the housing.
 7. An electronic apparatus for use in recordingand/or playing back at least one of audio and video signals, comprising:a housing having only six sides of which two opposite sides are a toppanel and a bottom panel arranged not parallel to each other; aplurality of support legs of differing heights arranged on the bottompanel such that the bottom panel is not parallel to a horizontal surfaceon which the electronic apparatus is placed; and a plurality of flat,rigid circuit boards installed in the housing, wherein at least one ofthe plurality of circuit boards includes a playback unit for playing adisk recording medium, wherein a main side of each of the plurality ofcircuit boards faces the top panel and the bottom panel of the housing.8. The electronic apparatus according to claim 7, wherein all remainingopposite sides of the housing are respectively arranged not parallel toeach other.
 9. The electronic apparatus according to claim 7, whereinthe plurality of circuit boards are arranged not parallel to each otherand arranged not parallel to any side of the housing.
 10. The electronicapparatus according to claim 7, wherein the playback unit has a diskrotating mechanism for rotating the disk recording medium, and the diskrotating mechanism is arranged so that the disk recording medium loadedthereon is not parallel to any side of the six-sided housing.
 11. Theelectronic apparatus according to claim 10, wherein the disk rotatingmechanism is arranged so that the disk recording medium loaded thereonis not parallel to the plurality of circuit boards.
 12. The electronicapparatus according to claim 10, wherein the disk rotating mechanism isarranged so that the disk recording medium loaded thereon is parallel tothe horizontal surface on which the electronic apparatus is placed. 13.An electronic apparatus for use in recording and/or playing back atleast one of audio and video signals, comprising: a housing having onlysix sides; and a plurality of rigid circuit boards, wherein at least oneof the plurality of circuit boards includes a signal processor unitmounted thereon and the plurality of circuit boards are arranged in thehousing to be not parallel to each other and not parallel to anyopposite sides of the housing.
 14. The electronic apparatus according toclaim 13, wherein two opposite sides of the housing are a top panel anda bottom panel arranged not parallel to each other.
 15. The electronicapparatus according to claim 14, further comprising: a plurality ofsupport legs of differing heights arranged on the bottom panel such thatthe bottom panel is not parallel to a horizontal surface on which theelectronic apparatus is placed.
 16. The electronic apparatus accordingto claim 13, wherein all remaining opposite sides of the housing arerespectively arranged not parallel to each other.
 17. The electronicapparatus according to claim 13, wherein the housing is shaped as a cubeand the plurality of circuit boards are arranged at an angle less than45 degrees from any opposite sides of the housing.
 18. The electronicapparatus according to claim 13, wherein the plurality of circuit boardsare substantially flat.
 19. An electronic apparatus for use in recordingand/or playing back at least one of audio and video signals, comprising:a housing having only six sides; a plurality of support legs ofdiffering heights arranged on a bottom panel of the housing such thatthe bottom panel is not parallel to a horizontal surface on which theelectronic apparatus is placed; and a plurality of rigid circuit boardsinstalled in the housing, wherein at least one of the plurality ofcircuit boards includes a playback unit for playing a disk recordingmedium, wherein a main side of each of the plurality of circuit boardsfaces two opposite sides of the housing.
 20. The electronic apparatusaccording to claim 19, wherein the plurality of circuit boards arearranged not parallel to each other and arranged not parallel to anyside of the housing.
 21. The electronic apparatus according to claim 20,wherein the two opposite sides of the housing facing the plurality ofcircuit boards are arranged not parallel to each other.
 22. Theelectronic apparatus according to claim 21, wherein the two oppositesides of the housing are a top panel and the bottom panel of thehousing.
 23. The electronic apparatus according to claim 19, wherein allremaining opposite sides of the housing are respectively arranged notparallel to each other.
 24. The electronic apparatus according to claim19, wherein each of the plurality of circuit boards are shaped as a cubeand arranged at an angle less than 45 degrees from the top panel and thebottom panel of the housing facing the plurality of circuit boards. 25.The electronic apparatus according to claim 19, wherein the plurality ofcircuit boards are substantially flat.
 26. The electronic apparatusaccording to claim 19, wherein the playback unit has a disk rotatingmechanism for rotating the disk recording medium, and is arranged sothat the disk recording medium loaded thereon is not parallel to anyside of the six-sided housing.
 27. The electronic apparatus according toclaim 26, wherein the disk rotating mechanism is arranged so that thedisk recording medium loaded thereon is not parallel to the plurality ofcircuit boards.
 28. The electronic apparatus according to claim 26,wherein the disk rotating mechanism is arranged so that the diskrecording medium loaded thereon is parallel to the horizontal surface onwhich the electronic apparatus is placed.